Adding in the cost of infrastructue I have just under $7 into each butcher ready rabbit. I butcher at 11-12 weeks with a live weight of 5-5.5lbs and a dressed weight of about 3lbs.
When I started with meat rabbits my goal was to have brood stock that produced 8-10 kits at birth, with 8 making it to market weight (5lbs) in 12 weeks, or less. My motto I always follow is, "Keep the best, sell the rest." "The best" to me means most litters there is a pick of the litter doe and buck, but not in all litters. Only sell your best (if you do not need replacement stock) and you will earn a great reputation as a meat rabbit breeder. There are very few who specialize in breeding meat rabbits that you'll will soon have waiting lists once your stock reaches market standards.
I keep a detailed journal for my rabbitry. When potential customers can read through my records, see all the litters the doe has had, what the buck produces, etc... this adds value to what you are trying to sell. I charge $35 for a pick of the litter doe, or buck, and sell them as soon as I list them for sale. $70 buys me three 50lb sacks of feed...that lasts a while!
I feed a corn free, non-gmo, 18% protein, alfalfa based pellet for about half of my rabbits calories. The rest is fodder from around the yard, crops specifically planted for them and my new favorite...sweet potato vines. Check this link out...
http://users.tamuk.edu/kfsdl00/Meat%20Rabbits%20Finished%20on%20Sweet%20Potato%20Forage%20Looks%20Good%20in%20Texas%20Research.pdf
To be cost effective my suggestions would be...
1) buy the best stock you can find
2) only keep the best to improve your stock, eat the rest
3) keep diligent records
4) feed fodder
5) plant crops just for the rabbits, or crops that you can share with the rabbits (radishes for me, tops for the rabbits)
The best results I have gotten is breeding a Californian buck to NZW does. This outcross produced 5lb kits for me in 10 weeks. HTH,
Joe